/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/


package org.apache.poi.hssf.record.formula.functions;

import org.apache.poi.hssf.record.formula.eval.AreaEval;
import org.apache.poi.hssf.record.formula.eval.ErrorEval;
import org.apache.poi.hssf.record.formula.eval.Eval;
import org.apache.poi.hssf.record.formula.eval.NumberEval;
import org.apache.poi.hssf.record.formula.eval.RefEval;

/**
 * Implementation for Excel COLUMNS function.
 * 
 * @author Josh Micich
 */
public final class Columns implements Function {

	public Eval evaluate(Eval[] args, int srcCellRow, short srcCellCol) {
		switch(args.length) {
			case 1:
				// expected
				break;
			case 0:
				// too few arguments
				return ErrorEval.VALUE_INVALID;
			default:
				// too many arguments
				return ErrorEval.VALUE_INVALID;
		}
		Eval firstArg = args[0];
		
		int result;
        if (firstArg instanceof AreaEval) {
            AreaEval ae = (AreaEval) firstArg;
            result = ae.getLastColumn() - ae.getFirstColumn() + 1;
        } else if (firstArg instanceof RefEval) {
            result = 1;
        } else { // anything else is not valid argument
            return ErrorEval.VALUE_INVALID;
        }
        return new NumberEval(result);
	}
}
